Commandante Fidel's departure from power, of course, will be solely a matter of biology, and the few pictures of him that have emerged since he took ill last year clearly show biology at work. When the end comes, change in Cuba could be as vast as any that greeted the end of the last century's great dictators.

Stalin, Franco, Tito, Mao: all were mostly alike in their means and methods. How they passed from the scene, however, was often very different, and these differences can shape societies for years and decades to come.

Consider the Soviet Union. On March 9, 1953, from the Gulf of Finland to the Bering Sea, everything stood still; likewise in Warsaw, Budapest, Prague, and East Berlin. In Beijing, Mao Zedong himself bowed low before an immense effigy of Joseph Stalin. Huge mourning crowds, crying, nearly hysterical, could be seen all over the vast empire Stalin had ruled.

Yet, within days, the word Stalinism was being expunged from a new Soviet dictionary, and three years later my grandfather, Nikita Khrushchev, denounced Stalin's "cult of personality" in his famous "Secret Speech" to the Communist Party's 20th Congress. The Khrushchev thaw that followed may have been short-lived, but for the first time in Soviet history the possibility of change was opened - a possibility that Mikhail Gorbachev seized upon.

The death of Marshal Josip Broz Tito brought forth an outpouring of another sort. For decades, his personal rule imposed a false unity on Yugoslavia. Following his death in 1980, that artificial state began to unravel, culminating in the genocidal wars in Bosnia, Croatia, and Kosovo of the 1990's.

Not all long-term dictatorships, however, end in disintegration and mayhem. Mao's death allowed for Deng Xiaoping's return from disgrace and internal exile. Deng quickly routed Mao's "Gang of Four" heirs, and in only a few years opened China's economy, fuelling a capitalist revolution that has transformed China far more completely - and successfully - than Mao's socialist revolution ever did.

Spain, too, escaped violent dissolution when Generalissimo Francisco Franco's fascist dictatorship collapsed at his death. Here the old dictator can take some credit, for by re-establishing the monarchy under King Juan Carlos just before he died, Franco provided Spain with a foundation on which to build anew. Little did Franco realise that what Juan Carlos would build, with the help of a clever young Franco-era bureaucrat named Adolfo Suarez, was the modern, democratic Spain of today.

It was no accident that communist countries were (and are) usually run by geriatric leaders, and democracies by younger men and women. That difference matters. Old leaders can preside successfully over smoothly running countries that need no radical re-examination of their policies and purposes.

Political competition makes it necessary for all politicians, whatever their age, to stay on their toes, anticipate new problems, and remain open to new ideas aimed at addressing them. No one can keep himself ensconced in high office subject only to death or his own boredom. One-party systems, one-man charismatic dictatorships, or a mixture of the two, as in Tito's Yugoslavia, are a guarantee of sclerotic minds and inert governments.

So what will become of Cuba after Fidel departs?

Many observers portray Raul Castro, Fidel's younger brother and designated heir, as a pragmatist - the "practical Castro". When Cuba's lavish Soviet subsidies vanished in the early 1990s, it was Raul who recognised that the regime's survival required economic reforms, pressing to allow private agricultural markets to reopen in order to boost food production and stave off possible starvation.

However, this is the same man who, as the head of Cuba's internal security apparatus, for many years represented the knuckles of an iron-fisted regime, directly responsible for imprisoning - and often torturing - thousands of dissidents. So perhaps the best that could be hoped for is a Russian-style experiment with liberalisation that is quickly called off by the regime's nervous Old Guard.

Moreover, with the support of oil-rich allies like Venezuela's President Hugo Chavez - and with the recent discovery of significant crude reserves off Cuba's own coast - introducing reforms could well become less urgent. In that case, Raul may seek to cling grimly to the fossilised system that he helped build and maintain with such brutality.

But Raul Castro is an old man himself, so we can hope for the prospect that some Deng or, better yet, a Suarez will ultimately emerge from the wreckage of Fidelism. But for now, younger communist officials, like Foreign Minister Felipe Perez Roque, remain ideological hard-liners whom many Cubans refer to as "los Taleban". If they take control and stick to their guns, Cuba could face another long biology lesson.

Nina Khrushchev is a professor of international affairs at New School University.

Copyright: Project Syndicate.

Nina Khrushchev

New York